public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
{
string strValue = value as string;
if (strValue != null)
{
object obj = null;
string text = strValue.Trim();
if (text.Length == 0)
{
obj = Color.Empty;
}
else
{
// First, check to see if this is a standard name.
//
obj = GetNamedColor(text);
if (obj == null)
{
if (culture == null)
{
culture = CultureInfo.CurrentCulture;
}
char sep = culture.TextInfo.ListSeparator[0];
bool tryMappingToKnownColor = true;
TypeConverter intConverter = TypeDescriptor.GetConverter(typeof(int));
// If the value is a 6 digit hex number only, then
// we want to treat the Alpha as 255, not 0
//
if (text.IndexOf(sep) == -1)
{
// text can be '' (empty quoted string)
if (text.Length >= 2 && (text[0] == '\'' || text[0] == '"') && text[0] == text[text.Length - 1])
{
// In quotes means a named value
string colorName = text.Substring(1, text.Length - 2);
obj = ExtendedColors.FromName(colorName);
tryMappingToKnownColor = false;
}
else if ((text.Length == 7 && text[0] == '#') ||
(text.Length == 8 && (text.StartsWith("0x") || text.StartsWith("0X"))) ||
(text.Length == 8 && (text.StartsWith("&h") || text.StartsWith("&H"))))
{
// Note: ConvertFromString will raise exception if value cannot be converted.
obj = ExtendedColors.FromArgb(unchecked ((int)(0xFF000000 | (uint)(int)intConverter.ConvertFromString(context, culture, text))));
}
}
// Nope. Parse the RGBA from the text.
//
if (obj == null)
{
string[] tokens = text.Split(new char[] { sep });
int[] values = new int[tokens.Length];
for (int i = 0; i < values.Length; i++)
{
values[i] = unchecked ((int)intConverter.ConvertFromString(context, culture, tokens[i]));
}
// We should now have a number of parsed integer values.
// We support 1, 3, or 4 arguments:
//
// 1 -- full ARGB encoded
// 3 -- RGB
// 4 -- ARGB
//
switch (values.Length)
{
case 1:
obj = ExtendedColors.FromArgb(values[0]);
break;
case 3:
obj = ExtendedColors.FromArgb(values[0], values[1], values[2]);
break;
case 4:
obj = ExtendedColors.FromArgb(values[0], values[1], values[2], values[3]);
break;
}
tryMappingToKnownColor = true;
}
if ((obj != null) && tryMappingToKnownColor)
{
// Now check to see if this color matches one of our known colors.
// If it does, then substitute it. We can only do this for "Colors"
// because system colors morph with user settings.
//
int targetARGB = ((ExtendedColors)obj).ToArgb();
foreach (ExtendedColors c in Colors.Values)
{
if (c.ToArgb() == targetARGB)
{
obj = c;
break;
}
}
}
}
if (obj == null)
{
throw new ArgumentException("Invalid ExtendedColors text");
}
}
return(obj);
}
return(base.ConvertFrom(context, culture, value));
}
/// <summary>
/// Creates a ExtendedColors structure from the specified 8-bit color values (red, green, and blue). The alpha value is implicitly 255 (fully opaque). Although this method allows a 32-bit value to be passed for each color component, the value of each component is limited to 8 bits.
/// </summary>
/// <param name="red">The red component value for the new ExtendedColors. Valid values are 0 through 255. </param>
/// <param name="green">The green component value for the new ExtendedColors. Valid values are 0 through 255. </param>
/// <param name="blue">The blue component value for the new ExtendedColors. Valid values are 0 through 255. </param>
/// <returns>The Color that this method creates.</returns>
public static ExtendedColors FromArgb(int red, int green, int blue)
{
return(ExtendedColors.FromArgb(255, red, green, blue));
}